# How do you use the amplitude and period to graph y = -cos ( x- pi/4)?

Mar 2, 2016

$A = 1 , B = 1 , C = 0 \to y = 0 , D = \frac{\pi}{4} , P = \frac{2 \pi}{B} = 2 \pi$ Increments: $\frac{P}{4} = \frac{2 \pi}{4} = \frac{\pi}{2}$

#### Explanation:

Start from the sinusoidal axis y=C which happens to be the x-axis here since sinusoidal equation is y=0. From y=0 go up one unit to y=1 and draw the upper bound then go down one unit and draw the lower bound. Your graph will start on the x-axis from $\frac{\pi}{4}$ and add $\frac{\pi}{2}$each time to get to the next mark. Remember that you only need five points to graph one cycle of the sinusoidal equation.